Jenkin, a British engineer, served as secretary of the British Association's Electric Standards Committee (formed in 1861), which was responsible for setting and naming the standard units of electrical quantity and resistance. Between 1858 and 1872 Jenkin worked in the design and manufacture of submarine cables, performing the first accurate measurements of the specific inductive capacity of gutta-percha (used in submarine cable insulation) in 1862. His letter requests information on the comparative qualities of two different types of submarine cable:

"Can you give me the exact gain which you derived in the Persian Gulf cable in the use of the segmented wire, i.e. what the discharge was with the common strand and 225 [illeg.] 275 S.P. and what the discharge with the segmented wire same weights? If not with those exact weights can you give me the exact ratio of the discharges in any two cases where the same weights of materials were used-of the exact weights of materials required to produce the same discharge?"